xen: changes to hvm code in order to support PVH guests

On PVH we don't need to init the shared info page, or disable emulated
devices. Also, make sure PV IPIs are set before starting the APs.

Approved by: gibbs
Sponsored by: Citrix Systems R&D

x86/xen/hvm.c:
 - Return early from functions that are no-ops on Xen PVH guests.
 - In order to make sure PV IPIs are setup before AP startup,
   initialize them in SI_SUB_SMP-1.

1 files changed, 42 insertions, 5 deletions

diff --git a/sys/x86/xen/hvm.c b/sys/x86/xen/hvm.c
index cb895e5..2d0df71 100644
--- a/sys/x86/xen/hvm.c
+++ b/sys/x86/xen/hvm.c
@@ -350,7 +350,7 @@ xen_setup_cpus(void)
 {
 	int i;
 
-	if (!xen_hvm_domain() || !xen_vector_callback_enabled)
+	if (!xen_vector_callback_enabled)
 		return;
 
 #ifdef __amd64__
@@ -422,6 +422,14 @@ xen_hvm_init_shared_info_page(void)
 {
 	struct xen_add_to_physmap xatp;
 
+	if (xen_pv_domain()) {
+		/*
+		 * Already setup in the PV case, shared_info is passed inside
+		 * of the start_info struct at start of day.
+		 */
+		return;
+	}
+
 	if (HYPERVISOR_shared_info == NULL) {
 		HYPERVISOR_shared_info = malloc(PAGE_SIZE, M_XENHVM, M_NOWAIT);
 		if (HYPERVISOR_shared_info == NULL)
@@ -498,6 +506,15 @@ enum {
 static void
 xen_hvm_disable_emulated_devices(void)
 {
+
+	if (xen_pv_domain()) {
+		/*
+		 * No emulated devices in the PV case, so no need to unplug
+		 * anything.
+		 */
+		return;
+	}
+
 	if (inw(XEN_MAGIC_IOPORT) != XMI_MAGIC)
 		return;
 
@@ -522,9 +539,19 @@ xen_hvm_init(enum xen_hvm_init_type init_type)
 		if (error != 0)
 			return;
 
+		/*
+		 * If xen_domain_type is not set at this point
+		 * it means we are inside a (PV)HVM guest, because
+		 * for PVH the guest type is set much earlier
+		 * (see hammer_time_xen).
+		 */
+		if (!xen_domain()) {
+			xen_domain_type = XEN_HVM_DOMAIN;
+			vm_guest = VM_GUEST_XEN;
+		}
+
 		setup_xen_features();
 		cpu_ops = xen_hvm_cpu_ops;
- 		vm_guest = VM_GUEST_XEN;
 		break;
 	case XEN_HVM_INIT_RESUME:
 		if (error != 0)
@@ -539,9 +566,15 @@ xen_hvm_init(enum xen_hvm_init_type init_type)
 	}
 
 	xen_vector_callback_enabled = 0;
-	xen_domain_type = XEN_HVM_DOMAIN;
-	xen_hvm_init_shared_info_page();
 	xen_hvm_set_callback(NULL);
+
+	/*
+	 * On (PV)HVM domains we need to request the hypervisor to
+	 * fill the shared info page, for PVH guest the shared_info page
+	 * is passed inside the start_info struct and is already set, so this
+	 * functions are no-ops.
+	 */
+	xen_hvm_init_shared_info_page();
 	xen_hvm_disable_emulated_devices();
 } 
 
@@ -573,6 +606,9 @@ xen_set_vcpu_id(void)
 	struct pcpu *pc;
 	int i;
 
+	if (!xen_hvm_domain())
+		return;
+
 	/* Set vcpu_id to acpi_id */
 	CPU_FOREACH(i) {
 		pc = pcpu_find(i);
@@ -616,7 +652,8 @@ xen_hvm_cpu_init(void)
 
 SYSINIT(xen_hvm_init, SI_SUB_HYPERVISOR, SI_ORDER_FIRST, xen_hvm_sysinit, NULL);
 #ifdef SMP
-SYSINIT(xen_setup_cpus, SI_SUB_SMP, SI_ORDER_FIRST, xen_setup_cpus, NULL);
+/* We need to setup IPIs before APs are started */
+SYSINIT(xen_setup_cpus, SI_SUB_SMP-1, SI_ORDER_FIRST, xen_setup_cpus, NULL);
 #endif
 SYSINIT(xen_hvm_cpu_init, SI_SUB_INTR, SI_ORDER_FIRST, xen_hvm_cpu_init, NULL);
 SYSINIT(xen_set_vcpu_id, SI_SUB_CPU, SI_ORDER_ANY, xen_set_vcpu_id, NULL);